I have a 16" RRA HBAR with 7" free floated DD Omega rail and am using the standard FSB. This is my SHTF rig. I've tried a few different light setups over the past year, and none have really worked for me for one reason or another. I'm now toying with the idea of mounting a light to the FSB. I'm thinking of mounting the light in a Larue QD mount off the FSB at the 11 O'clock position. My thought process is, if it's night time or I'm entering a building, I can snap the light onto the FSB. If I'm at the range for the day and/or hiking with the rifle during the day, the light can be detached and stashed away somewhere, shaving some weight off the rifle (same for my 3X flip-to-side EOTech magnifier). Additionally, the light can still be utilized as a regular flashlight when not mounted to the rifle.





Aside from welcoming other suggestions, my primary question is regarding POI shift when the light is mounted. The total weight of the mounted light should come to around 8 oz. give or take (I'm presently considering a 4Sevens Maelstrom). I thought I would zero the sights without the light mounted, and accept the POI shift as a penalty when the light is mounted, given that shooting distances in dark environments are likely to be shorter, making any POI shift less of an issue.





Any thoughts on how much of a shift I might expect from with my FF HBAR? Am I thinking about this the wrong way or am I over thinking it?





I'd consider leaving a light mounted all the time (and regardless of the solution, it will be stored with the light mounted), but I'm admittedly still pretty shaky when shooting off-hand, and the weight savings seems to help. The ability to keep the rifle light weight and tack on toys as the situation warrants also seems advantageous. I know I could go with a lighter profile barrel, but I'm not willing to go there quite yet. I could also look at a smaller, lighter weight light that I could mount permanently (I tried my TLR-2s already), but the switching controls didn't work well for me with my thumb-break grip, and a light with more throw seems prudent given my environment (a wide open rural neighborhood).





Thanks for your thoughts in advance!
 

I think you're over thinking it. I don't shoot long range or from a bench, just patrol rifle distances out to 200yds and I've never noticed POI shift running a FSB mounted light v. no light.  I've used a FSB rail with surefire x200 and 6p mounted and used the classic surefire FSB mounted lights with no noticeable POI shift.  

Excellent, just the experience I was looking for! Thanks pointman!

I’ve done this and am pretty happy with the results.  The positioning of the light works well and the ability to mount it only when I need it is nice.  I haven't noticed any shift in the POI but I've only run a couple of hundred rounds though it so far and all of those at 100 yards or less.

I have a 16" Colt AR and notice no POI shift out to 200 yds on steel Poppers with an old school SureFire FSB-mounted classic weaponlight.

Battlecloth, any issues with the bezel mounted so close to the flash hider? The blast residue from a mere 9mm pistol quickly coated my old SF pistol light and the metal bezel's knurling was noticeably eroded as well.

I'm sure this would be an issue but the can goes on when the light goes so it's not been a problem.

Thanks for the responses everyone!

Just make sure you leave the light on there when you train.  You should always train with your gun as you would use it in the field/SHTF.  Your gun will handle differently with the added weight of the light, as it effects balance, momentum, etc.   No sense in removing it at the range.  All my rifles have lights permanently on them at all times and I never remove them.  

Same thing goes for pistol with weapon lights.  It does the user no good to only use a light for home defense and not at the range as it changes everything about the pistol weight and recoil.